Abstract: A method of manufacture of 3,5-bis(trifluoromethyl)bromobenzene, comprising the addition of a brominating reagent to a mixture of 3,5-bis(trifluoromethyl)benzene together with at least one of sulphuric acid or oleum in the absence of acetic acid. A method of production of 3,5-bis(trifluoromethyl)acetophenone comprising the reaction of 3,5-bis(trifluoromethyl)phenyl magnesium bromide with acetyl chloride in the presence of cuprous chloride. A method of production of 3,5-bis(trifluoromethyl)acetophenone comprising the steps of reacting 3,5-bis(trifluoromethyl)phenyl magnesium bromide with acetic anhydride, adding water, and recovering the product by azeotropic distillation. A method of removal of impurities including 3,5-bis(trifluoromethyl)acetate, 4-bromobutyl acetate and 4-chlorobutyl acetate from a preparation of 3,5-bis(trifluoromethyl)acetophenone, the method comprising heating the 3,5-bis(trifluoromethyl)acetophenone with a dilute solution of alkali.